If you have a lot of documents you're trying to organize, put them all together in one folder, rather than separating by filetype. Self-management site Mind Tools has more:

For example, store Word documents, presentations, spreadsheets, and graphics related to a particular project in a single folder - rather than having one folder for presentations for all projects, another folder for spreadsheets for all projects, and so forth. This way, it's much quicker to find, open, and attach documents for a particular project.